Method for the hydro-electrolytic treatment of ores.



R. R. GGODRICH.

METHOD FOR THE HYDRO ELECTROLYTIC TREATMENT 0F DRES. APPLICATION FILEDIAY 25, |915.

Heater L60 F/zwmy Step gi-1s rum Inc. mum nunmal. L

R. R. GOODRICH. METHOD FOR THE HYDROv ELECTROLYTIC TREATMENT 0F ORES.

APPLICATION FILED MAY 25, 1915.

Patented Feb. 15, 1916.

` n. n. GoonmcH. METHOD FOR THE HYDRO ELECTROLYTIC TREATMENT 0F ORES.1,171,782.

APPLICATION FILED MAY 25| 1915.

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R. R. GUODRlC'H. METHOD yFoRATHE HYDRO ELECTROLYTLC TREATMENVGF GRES.

*l f APPLICATIQN FILED MAY 25; 1915. I 1,171,782.

Patented Feb. 15', 1916, 4 SHEETSSHEE wann ROBERT GODRICH, 0FIUCSON,'ARIZONA.

lIIEILIIIQID B TH HYDRO-ELECTROLYTIC TREATMET 0F ORES.

Specication of Letters Patent.

- Patented Feb.'15,1916.

Application led lay 25,1915. Serial No. 30,446.

'To all 'whom it may concern:

Be it known that I, ROBERT RHEA Goon- RICH, a citizen of the UnitedStates, residing at Tucson, in the county of Pima andr State" ofArizona, have invented certain new and useful V,Improvements in Methodsfor the Hydro-Electrolytic Treatment of Ores, of which the following isa specification. y

This .invent-ion relates to a method of treating ores, and in its moreintense aspect to a hydro-'electrolytic process oftreating copper ores.1 'e One of the objects of the present invenvtion -is to provide asimple and practical proce of electrolytically treating metallic ores.

Y Another object is to provide a highly eliicient process which may beperformed at a minimum amount of expense and time.

A further object lis to provide a commercially practicable process forextracting the values from ores in a hydro-electrolytic manner.

A further object is to provide a process of the above character whichmay be carried out in steps. where in each step the met-al contents ofthe electrolyte and the current density are substantially constant.

A further Objectis to carry out such proc- Y ess with a minimum amountof power consumption. y

Other objects will be in part obvious and in part hereinafter pointedout in the following detailed explanation. J

' The invention accordingly consists in the features of construction andcombination of parts in the unique arrangement of steps and the relationof each step to each other, as will be indicated in the appendedclaims.' V'Io enable others skilled in the art so fully to comprehendthe underlying features ,thereof that they may .embody the same' bynumerous modifications in structure and relation contemplated by thisinvention, ldrawings depicting diagrammatically sev- Ieral forms andarrangements of the appa- .'atus have been annexed as part of thisclosure, and in such drawmgs like characters of reference denotecorresponding parts throughout all the views, of which- Figure l is adiagrammatic lview showingv .the complete apparatus, with its electricconnections and circulatmg means, so far as necessary to understand thepresent invention. Fig. 2 is a similar view (but with more cells)showing circulation meansbut not showing electric connections, Fig. 3 isa similar view showing an apparatus with the cells arranged for adifferent geometrical ratio of the metal contents of the electrolyte ofthe different steps. Fig.l 4 is a similar view showing the cellsarranged to suit an arithmetical diii'erence ing-metal contents of theelectrolyte of the steps. Y Referring now in. detail to the accompanying drawings and more particularly to Fig.

1, a brief description of the apparatus shown therein will be given inorder that a clearer understanding of the process hereinafter describedmay be had.- In this drawing 5 designates a` tank adapted to contain thecopper solution which is supplied or lilled directly from ore leachingtanks, not shown. A pipe 6 leads from the lower part of this tank to asecond tank 7, which will hereinafter be referred to as No. l steptemperature tank, which is 'provided with heating means 8 formaintaining the same at a substantially constant'temperature ofapproximately degrees centigrade, in order to more efficiently carry outthe present proc-l ess. A pipe 10 leads from thistemperature tank to thefirst of a series of four electrolytic cells 11, connected at theirlower ends by intervening pipes 12, thereby permitting a continuouspassage of the electrolyte therev 16 hereinafter referredfto as No. 2step temf means 17. A pipe 18 is provided fm2/conductmg the. solutionfrom thislftemperature tank to the lower part of a single electroV lyticcell 20, having four times the electrode area, as Will presently beexplained, otI each cell 11. An outlet pipe 21 communicates with acirculating pump 22 for circulating a portion of the solution backthrough pipe 23 to temperature tank 16. An overiow pipe 24 conducts a'portion of the solution to a sump tank 25. his solution from which alarge part of the copper has been removed may be drawn oil' to leachfurther copper ores, or it may ass through a. pipe 26 provided with a vave 27 into a tank 28, which may be referred to as finishing steptemperature tank, being also provided with heating means 30. A pipe 31is adapted to conn `vey the solution from tank 28 to a still larger cell32, provided with a circulating pump 33, for continuously circulatingthe lsolution through pipe 84.- back to the finishing step temperaturetank again and again until the copper is completely removed. A bypass 35leading to a barren solution tank 36 may be provided il desired, fromwhich the barren solution may be conducted to the ore leaching tanks. Agenerator 37 is provided at any convenient point and is preferablyconnected with the cells in substantially the manner shown. That is allof `the cells are connected in series While the electrodes of each cellare connected in parallel. The circulating pumps may be operated in anydesired mannerysuch for example as motors directly connected therewithand not herein shown.

The apparatus. shown in Figs. 2, 3 and 4 are substantially the same ingeneral structure, electric Wiring, etc., and it is believed to beunnecessary' to describe these in detail. Their operation andfdifferencein arrangement Willv be apparent from the de scriptionof the operationthereof and the following` discussion of the processl in connectiontherewith.

Taking up now the process adapted to be carried out in the apparatusshown in Fig. 1, it may be noted that theelectrolysis of the coppersulfate solution, which may be taken as ,an example, resulting from theleaching of copper ores, is conducted in steps, through electrolyticcells connected in series, with the electrodes of each individual cellconnected in parallel. In each step the composition of electrolyte ismaintained substantially constant in both copper and acid by means ofthe unique arrangementl of circulating systems of the electrolyte. Oneof these circulations may be called the step circulating or inter-stage,and comprises a circulating pump and intervening connections for drawingthe electrolyte from the contents 0156.0 per cent.

lastcell of the step and returning it to the temperature 1.tankWhihiniaintains the tempxeratureuof the system constant, and fromWhxic'hit:overflowsand gravitates into the firsticellofthe step. "'I'Theother circulation may be calledintra-stage system. wherebv' theelectrolyte progressespln-ough vthe plant. Here the coppersolution.resulting from tluleaching of the o re, after passing4 throughthe cells in the first step overflows into No. 2 step temperature tank.In other words the copper solution result-ing from th l leaching oftheore is run, together with the dis charge of the No. 1 step circulatingpump 12. into theelevated ten'lperature tank ot No; 1 step, vthusthere-enters the first cell ot' the step more solution `thanis drawnaway hv pump 13, and consequentlythelralance. of an equivalent amount ofsolution, leaves the last cell of the step by Way of over-floul ,pipe 15into temperature tank 16 -of Xo.` L step. Finally the last cell of thestep precedingy the finishing step No. 2 in this, case) over.

flows an amount of solution equal in amount i to the inflowing ture tank7.

The copper contents of the electrolyte from that ofthe copper solutionfed .to No. 1 stepv to that of the electrolyte of the last step,excepting the iinishing step, is main.- tained in geometrical ratio.plished by placing in series in each succeeding step a different numberot' cells.. The number of cells of each succeeding step `ilecreases inthe same geometrical ratio as the copper -contents of the electrolyte oithc copper solution to temperastep, While at the same time the area oi'the electrode surface is adjusted so that the cur! rent density isproportional to the copper contents. Since the `same current passesthrough every cell., the cells of ,the first step have a comparativelysmall area oi' electrode surface, While the cells of the last step have'a much larger area.

In designing afplant, any geometric factor, such as or or arithmeticaldiiierence, may be used.` For convenience, and as shown in Fig. 1, thegeometric factor 3g is used, and by Way of example it `may be as sumed.that the copper. solution resulting from the leaching of the ore hasy a`copper Then the elec- This is accomlos trolyte of No.1 step Willcontain onefo`urth of lthis copper contents. or 1.5 per cent. Let v ususe four cells in series each Withone cathode, as shown; a suitablecurrent density for this step is selected governed by the coppercontents of the electrolyte, since it is desirable to maintain currentdensity proportional to the coppercontents of the elec trolyte. Thisselection of current density fixes the strength of the current.

Letus select for No. 1 step: cathode area per cell=0.082ft sq. ft.;current densityainperes per sq. ft. Then, the current strength=0-082420=148 amperes. In No. 2 step the electrolyte has ,1g the coppercontents that it had in No. 1 step. Since current density is to be heldproportional to copper contents of the electrolyte, this requires to beused in No. 2 step cathode area per cell=0.0824 4:0.3296 sq. ft. Sinceall the cells are connected in series the saine current (1.648 amperes)that passes through the cells of No. 1 step likewise passes through thecells of No. 2 step, consequently the current density in No. 2 step:

amperes per sq. ft.

This is what is desired. The copper solution is fed to this step (No. 1step) at such a rate that the copper deposited on the electrodes amountsto three-fourths of the entering copper. Tlie electrolyte circulating inthe step thus remains constant in copper contents, likewise in acid, andthe solution overflowing is of the saine composition as the stepelectrolyte and in volume equal to that of the intlowiiig copper feedsolution.

The solution fed through pipe 15 to No. 2 step contains 1.5 per cent. ofcopper, being the overiiow of No. 1 step, but the electrolyte of No. 2step will contain but onefourth of this amount or 0.375 per cent., sincethe adjustments of the plant' are such that there is deposited in No. 2step, threefourths of the copper fed to it. In order to maintain theelectrolyte of this step constant, one-quarter as much copper must bedeposited on the cathodes of this step, which may be accomplished byplacing one-quarter as many cells in series, that is one cell havingfour cathodes, containing a cathode area of four times that of a cell inNo. 1 step, since the electrolyte has one-quarter the copper strength.This may be tabulated as follows: 1. Geometric factor equals ily '2.Copper feed solution resulting from leaching ore of 6.0 per cent. coppercontents.

No. 1 step. No. 2 step. Flltlgng Copper remaining in electrolyte,reported as per cent. of that ineed..... 2a 6. 2a i) No. l. step l\o. 2step Finishing only. only. step only. Copper extractcd,reported as percent. of that in feed..... 7a 18. n 6. 2.)

i Ngs'tl and in reps s eps. Copper extracted total, re-

poi-ted as percent. ofthat m i feed V 7a 93. i5 100 tion overflowingfrom the secoiidstep contains but 6.25% of the `original coppercontents,and if desired this solution in lwhich per feed solution. However, if itshould bev desired to extract the copper to the last trace al finishingstep may be employed. This step is supplied intermittently-'With acharge of solution from the sump tank 25, where the solution overflowingfrom cell 20,'No. 2 step, has collected. .This charge of solution iscirculated in the nishing tank continuously by a circulating pump in thesaine manner as in the preceding step, but with neither feed noroverflow, for a length of time depending upon the volume of electrolytein the system, or until all of the copper contents is deposited on thecathode. The solution barren in copper may be drawn od into tank 36 whendesired, after which a new charge is supplied from the sump tank throughconnection 26.

In order to simplify the preceding description, the question ofevaporation of the electrolyte in passing through thesystem has beeneliminated. In practical operation of the plant the values of thecomposition of the electrolyte will vary somewhat from i geometricalratio, depending upon the method adopted for'compensating forevaporation. Y

. It is the desideratum of metallurgists ,to secure in thehydroelectrolytic extraction of copper from its ores with insolubleanodes, conditions comparable with thosewhich are obtained in theelectrolytic reining of copper with soluble anodes. In the `presentprocess these conditions are more nearly approached than heretofore.These desirable conditions are: first, constant composition ofelectrolyte With currentdensity adjusted to suit composition; andsecond, small power' consumption. The present step system arrangementaccomplishes the first and, like in electrolytic refining of copper, theelectrolyte may be, circulated at any desired rate. A. rapid rate ofcirculation is made possible in the present system, together with theadjusting of the current density proportional to the copper contents,Which is heldv constant in each step and makes pos.-

- sible the securing of high current eihciency.

. electrolyte, namely, that rthrough the plant From this table it isyseen thatthe soluinsufficient for the securing of the best.

sults. Moreover the electrolyte, due to the slovs1 progress through thecells, would vary in composition in different parts. So although linthese processes the aim has beenl to maintain the current densityproportional to the copper contents, it has not really beenaccomplished.

The arrangements of the plant are such that: 1. Rapidcirculation ismaintained by the step circulating system. 2. The compositin ofelectrolyte remains constant in each step of the system. 3. The currentdensity is held strictly proportional to the copper contents.

In the arrangement shown in Fig. 2 ofthe drawings, the same geometricalratio is employed, but With a different number of cells in each step,from the example shown in Fig.

hours, extract all the copper from the solul tion supplied in twelvehours by the overiow of No. 2 step. It however, the plant is arranged asshown in Fig. 2, with three times as many cells as in No. l and No. 2steps, the volume of copper solution fed to No. 1 step would have VVbeenthree times as large, and likewise the overflow of No. 2 step would havebeen three times as large. The one cell of the finishing step wouldtherefore be obliged to operate continually in order to keep up itswork.

The following tabulated disclosure of operation and results attainedlby4 the arrangement shown in F ig. 2 may be most conveniently set forthas follows:

` Example of step arrangement of plant. Composition of he electrolytesof the stepsheld 'in geometrical ratio i,

v (except thejlm'shing step.)

Feed copper solu 7 N o. 1 step. No. 2 step. Fuslhmg non. P-

Relative copper contents oi electrolyte. 1 i .11ir ,1 t0 0 Coppercontentsoi electrolyte, per cent 6. 0 1. 5 0. 375 O. 375 to 0 H2SO4contents of electrolyte ner cent... 0 6. 93 8. 66 S. 66 to 9.21 Copperremaining in electrolyte expressed as pe en of that n feed 25, 6. 1:1 0@opper deposited, expressed as per cent. of that in leed 7o Y 1R. To 6.25

(All steps.) Total copper deposited lexpressed as per cent. of that infeed 7E 91j. 75 10Q Number'of cells in series in each step. X Relativeelectrode area per cell l 4 s Relative current density 1 i g N. B. Vhenusing carbon anodes with sulfur dioXid gas, acid contents will be higherthan given in these samples.

In Fig. 3 there is shown diagrammatically an apparatus which4 in generalstructure is substantially the same as that shown in Fig. 1, the cellsare connected in series and the electrodes of the individual cellsconnected in parallel. The number 'of cells however in each step isdifferent and .further steps are added. The copper contents of theelectrolyte of the steps is maintained in geometrical ratio if,likewise.y

the number of cells of the succeeding steps is maintained in the samegeometrical ratio, while the electrode area per cell of each` step isdouble the electrode area per celly of the preceding step. Thus thecopper contents of the electrolyte of each step is maintained constantand the current density is maintained proportional to the copper'contents of the electrolyte.

This arrangement and operation may be tabulated as follows:

Example of step arrangementof plant. Composition of the electrolytes ofthe steps held rin geometrical ratto i,

' v (except the finishing step.)

Feed co per sold)- No. 1 step. No. 2 step. No. 3 step. No. 4 step. tion.

Relative co r contents of electrolyte 1 l ,l5 11*E t0 0 Copperconiiialiilss of electrolyte, per cent 6. O 3.0 1. o 0.75 0.375 0.37.9to 0 H1304 contents of,electro1yte, per cent. 0 4.62 6.93 8.08 8. 668.66 to 9.24 Copper remaining in electrolyte, expressed as per cent. fthat in feed gg g o g t f a a Copper deposited, expressed as per cent ofhat n1 eed Y land (Nos. l, 2 (NOS. 1, 2!

02 s and 3 3, and 4 (All steps.)

. p steps.) steps.) Total copper deposited, expressed as per cent. ofthat in feed. 50 gg. 5 gg. 7a 1(3)? Number of cells in'series of eachstep X --2 4- sa Relativa electrode area per cell 1 2 8 16 Relativecurrent density 1 t. A

In Fig. 4 there is shown a. further form ofapparatusin -which the coppercontents uof the electrolyte of the steps are ma1ntained in arithmeticaldifference of 1.5. The number of cells in each step remains the same butthe electrode area of yeach cell is .Example of step arrangement ofplant.

Composition of the electrolytes of the steps held in arithmet'icaldiference,

1.5 per cent., (except the finishing step.)

Feed copper Solution. No. 1 step. No. 2 step. No. 3 step. ruslglngRelative copper contents of electrolyte... L.

' l 1 .';`;-....j Cogper contents `of electrolyte per cent. 6. 0 4L 53.0 1. 5 1.5 to 0 H O4 contents of electrolyte, percent. 0 2. 31v 4. 625 93 6. 93 to 9. 24 C0 per remaining in electrolyte, expressed as percent. of that in i 75 'o 2f o Copper deposited, expressed as per cent.of that in feed 25 g5 2g 25 (N2ost. 1 and (Ntps. 1, 2, (All steps.) l :l't

Total copper deposited, expressed as per cent. of that in feed 25 s epb)n 3 s s 10 Number of cells in series in each step 1' X X X Relativeelectrode area per cell 1 1 5 3 6 1 1 1 R l 1 e atlve current density y1 1' 5 3 6 4 From the above disclosure it 'will be seen that the presentinvention comprises a simple and practical apparatus so arranged andproportioned as to permit the carrying out of the process hereindisclosed in a manner designed to accomplish, among others, all of theobjects and advantages above set forth.

Without further analysis, the foregoing -will so fully reveal the gistof this invention thatothers can by applying current taining acirculation throughout an entire system of cells while simultaneouslycausing an independent circulation of electrolyte in each of a number ofgroups of cells.

2. The herein described method of depositing a metal electrolytically bymaintaining a circulation throughout the entire system of cells whilesimultaneously causing an independent circulation of electrolyte in eachof Va number of groups of cells, and 4,5

maintaining the composition of an electrolyte constant during itscirculation in each group.

3. The herein described method of depositing a metal electrolytically bymaintaining a circulation throughout the entire system ofcellswhilesimultaneously causing an independent circulation of electrolyte to eachof a numberof groups of cells provided with different electrode surfaceareas in each group.

4: The herein described method of deposltlng a metal electrolytically bymaintalning a circulation throughout the entire system of cells Whilesimultaneously causing an independent circulation of electrolyte in eachof a number of groups of cells provided With increasing electrodesurface, said first circulation maintaining an inflow of solution toeach group suitable to the current strength thereof.

5. The herein described method of depositing a metal electrolytically bymaintaining a circulation throughout the entire system 'of cells inwhich the electrodes of the groups of cells of each are connected inseries and thev electrodes of each cell are connected in parallel Whilesimultaneously causing an independent circulation of electrolyte in eachgroup of cells.

6. The herein described method of depositing a metal electrolyticallywhich consists in step grouping cells of increasing electrode area,maintaining constant the composition of electrolyte in each group andsimultaneously causing inter and intra circulation in said groups.

7. The herein described method of dependent circiilationof electrolytein each of a number of groups ofcells having progressively increasingelectrode surface area.

a flow of solution between adjacent groups suitable to the currentstrength, and maintaining the compositionvy` of electrolyte in eachgroup substantially constant by means of a simultaneous and independentcireu-z lation of electrolyte in each group of cells.

In testimony whereof I aiiiX my signature in presence of two Witnesses.

ROBERT RHEA GOODRICH.

Vitnesses ANNA BLACK, JOHN J. RANAGAN.

